Sagot :
In any redox reaction, the substance that undergoes reduction will 3) gain electrons and have a decrease in oxidation number.
redox reactions deal with the transfer of electrons from one species to another species
redox reactions are made of reduction reactions and oxidation reactions
reduction reactions are when electrons take in electrons and results in a decrease in the oxidation number
oxidation reactions are when electrons give out electrons resulting in an increase in the oxidation number
therefore correct answer for reduction reactions are
(3) gain electrons and have a decrease in oxidation number